Yes, I do this. It's a self-calming thing for me. It is a stim IMO. I usually find I focus on something that is high contrast; light reflecting off metal. I also do it with lights, holding the light in peripheral vision, not usually looking right at it. Things with closely spaced bars. Frames on walls. Blinds. Windows in general. Ceiling fans when on or off. The place where the wall meets the ceiling. Door frames. And so on.
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RDOS Aspie Score: 145 or 144/200 Aspie, 68 or 57/200 NT
Defies categorization. A mixed bag.